1. Field of the Invention
This invention is a process for the ethoxylation or propoxylation of compounds containing active H atoms. In particular, the invention is a process using a catalyst system comprising esters of titanic acid and/or zirconic acid.
In the context of the invention, useful compounds containing active H atoms, upon alkoxylation form surfactants. Useful compounds include fatty alcohols, Guerbet alcohols, fatty acids and fatty amines which, on ethoxylation or propoxylation, form nonionic surfactants. A typical example is the reaction of fatty alcohols containing 10 to 18 carbon atoms with several mols of ethylene oxide and/or propylene oxide in the presence of a catalyst.
2. Description of Related Art
The polyalkoxylation reaction has been carried out using catalysts such as calcium and strontium hydroxides, alkoxides and phenoxides (EP-A No. 00 92 256), calcium alkoxides (EP-A No. 00 91 146), barium hydroxide (EP-B No. 0 115 083), basic magnesium compounds, for example alkoxides (EP-A No. 00 82 569), magnesium and calcium fatty acid salts (EP-A No. 0 85 167), antimony pentachloride (DE-A No. 26 32 953), aluminium isopropylate/sulfuric acid (EP-A No. 22 81 21).
Other typical polyalkoxylation catalysts are potassium hydroxide and sodium methylate.
The known catalysts have the disadvantage that they are difficult to incorporate into the reaction system and/or are difficult to produce. In addition, where alkali hydroxides and alkali alcoholates are used, the range of the degree of polyalkoxylation, i.e. the homolog distribution, which will be discussed in more detail hereinafter, is broad. Although acidic catalysts, for example antimony pentachloride, bring about a narrower homolog distribution and a lower fatty alcohol content of the reaction products, they are highly corrosive and, in some cases, toxic. Although, where mixtures of aluminium alcoholates and sulfuric acid are used, it is possible to obtain a narrow homolog distribution in the alkoxylation products for high conversion levels in the case of linear fatty alcohols, the same does not apply to branched alcohols, for example, Guerbet alcohols.
A narrow range of the degree of polyalkoxylation is particularly important for fatty alcohol polyalkoxylates, cf. JAOCS, Vol. 63, 691-695 (1986), and HAPPI, 52-54 (1986). Accordingly, the alkoxylates having a narrow range of homolog distribution, have the following advantages:
low pour points,
relatively high smoke points,
require fewer mols alkoxide to achieve solubility in water,
require lower quantities of hydrotropes to achieve compatability with liquid universal detergents,
have a relatively faint odor due to the presence of free (unreacted) fatty alcohols
reduces pluming in the spray-drying of detergent slurries containing fatty alcohol polyalkoxylate surfactants.
The homolog distribution of fatty alcohol polyalkoxylates is related to the type of catalyst used. A measure of the homolog distribution is the Q value according to the following relation: EQU Q=n*.multidot.p.sup.2
in which n* is the average number of adducts (averge degree of ethoxylation) and p is the percentage of adduct ethoxylated to a certain degree, which is predominantly formed. Accordingly, a high Q value signifies a narrow homolog distribution range.
Ethoxylates having a low content of free fatty alcohols have an increased conversion level in the production of ether carboxylic acids by reaction of the ethoxylates with sodium chloroacetates in the presence of alkali hydroxides. In addition, narrow-range ethoxylates are extremely effective thickeners for surfactant solutions.